In many rotary driven comminution devices, comminution is achieved, in whole or in part, by grinding or crushing the material, as described in the following five US Patents.
In U.S. Pat. Nos. 3,480,841 and 3,608,841 by Wageneder, the spatial mounting of the grate and rotor within the housing define a converging orbital clearance into which the material is forced by the rotor and thus crushed between the blades of the rotor and the grate. The Wageneder invention is not designed to maximize lifting and flinging of the material toward a breaker bar. In operation, the rotary grinding and crushing function of the Wageneder apparatus impedes the lifting and centrifugal flinging of material into a clear trajectory as is desired in my invention.
In U.S. Pat. No. 4,373,678 by Reitter, Reitter, like Wageneder, relies on a converging orbital path to crush and grind the material. Again, Reitter's invention is not designed to maximize lifting and flinging of the material at a breaker bar; and, like Wageneder, Reitter's apparatus, in operation, impedes the lifting and flinging of material through its rotary grinding and crushing function.
In U.S. Pat. No. 4,934,614 by Lewis, Lewis, like Reitter and Wageneder, relies on a close orbital path to crush the material. Lewis uses a plurality of breaker bars, rather than a sole breaker bar; and, in particular, Lewis does not teach the advantage, as I have discovered, of using a sole breaker bar in combination with the establishment of a clear-trajectory material path for flinging the material at the sole breaker bar. Lewis teaches away from my discovery by using a second grinding chamber in which the comminutable material pools. Pooling of the material inhibits and impedes the establishment of a clear-trajectory material path as does the use of multiple breaker bars.
In U.S. Pat. No. 4,093,127 by Alberts, et al., Alberts teaches the use of a rotary driven means arranged to maximize particle-to-particle impact and to minimize impact of the particles with the structure of the machine. Thus, Alberts teaches away from my invention since my invention is designed to minimize particle-to-particle impact.
In other rotary driven comminution devices, comminution is achieved by impact but through the use of centrifugal force, as described in the following U.S. Patents.
In U.S. Pat. No. 4,090,673 by Ackers, et al., Ackers describes a vertical shaft mounted impeller table impact crusher which uses a plurality of breaker bars (referred to as stationary anvils by Ackers) mounted circumferentially around the impeller table. Ackers does not teach the use of clear-trajectory material path or the creation of a comminution environment within the apparatus which minimizes turbulence and particle-to-particle impact.
In U.S. Pat. No. 4,373,679 by Kawano, et al., Kawano, like Ackers, describes a vertical shaft mounted table impact crusher. However, Kawano, unlike my invention, relies on the material's impact with the blades on the rotor table, rather than a stationary breaker bar, to achieve shattering and comminution.
Rotary driven impact comminution has also been described with the use of a horizontal shaft and rotor in U.S. Pat. No. 4,151,959 by Deister. Deister teaches the use of a rotor with an essentially continuous blade angularly graduated or stepped along the rotor. The Deister rotor and invention encourages and promotes, in general, a turbulent environment wherein material is ricocheting off of the various interior walls of the housing striking other material in the process. Deister relies on the particle to particle impact to achieve comminution. Deister also teaches away from my invention in that Deister discourages the use of a round cross-sectional housing. As will be seen, my invention relies on a generally round cross-sectional housing to create a clear tangential material path trajectory to the sole breaker bar.
A dual-shaft rotary driven comminution machine has been tested by British Petroleum (the "BP Machine") and is somewhat described in a video film produced by British Petroleum. Although the internal design and workings of the BP Machine are not fully disclosed or described in the video film, the film indicates that the BP Machine intends to achieve comminution through the convergence of two centrifugal pump streams. In other words, the BP Machine relies on particle-to-particle impact to achieve comminution. In particular, the two centrifugal pump streams are, in part, created and directed at each other by the shape of the internal roof of the comminution chamber--a dual arched-shaped roof which serves to direct the two streams toward each other. The BP Machine thus teaches away from my invention in that my apparatus achieves comminution by attempting to minimize particle-to-particle impact and by specifically replacing the center portion of the dual-arched roof chamber of the BP Machine with a near-flat roof.